RGB/TTL interface

• http://bugs.libre-riscv.org/show_bug.cgi?id=5
• https://opencores.org/project,vga_lcd full linux kernel driver also available
• https://github.com/freecores/vga_lcd/tree/master/rtl/verilog appears to be BSD-licensed.
• RGB/TTL up to 1440x900 @ 60fps, 24-bit colour